var util = require('util')

function Base() {
    this.name = 'base'
    this.base = 1991

    this.sayHello = function() {
        console.log('Hello' + this.name)
    }
}

Base.prototype.showName = function() {
    console.log(this.name)
} 

function Sub() {
    this.name = 'sub'
}

util.inherits(Sub, Base)

var objBase = new Base()
objBase.showName()
objBase.sayHello()
console.log(objBase)

var objSub = new Sub()
objSub.showName()
// objSub.sayHello()
console.log(objSub)